BLENCOWE, WILLIAM (1683–1712), decipherer, was the third son of Sir John Blencowe [q. v.], knight, baron of the exchequer, by the eldest daughter of the mathematician and decipherer. Dr. Wallis, and was born on 6 Jan. 1682-3. He was educated at Magdalen College, Oxford, where he graduated B. A. in 1701 (List of Oxford Graduates), On the nomination of Archbishop Tenison he became a fellow of All Souls, 21 Dec. 1702, and he was made M.A. in 1704. He was instructed in the art of deciphering by his maternal grandfather, and for his encouragement in the art received the survivorship of his pension of 100l. a year. Wallis died 28 Oct. 1703. As a matter of course Blencowe therefore succeeded him as decipherer to the government, and the statement of a survivor (Gent. Mag. lviii. 586) that he applied for the office 'unrecommended' cannot therefore be accepted as an accurate representation of facts. The salary he ultimately received for the office was 200l. a year (Archives of Ail Souls, 346). He desired a dispensation permitting him to retain his fellowship at All Souls w^ithout taking holy orders, and on the warden interposing his veto the queen interfered on his behalf. Ultimately the dispute led to the abolition of the warden's veto on dispensations, and the non-residence of the fellows became from that time a leading characteristic of All Souls College. The statement of Noble that at the trial of Bishop Atterbury he exercised his skill in deciphering certain papers is a mistake, the trial having taken place ten years after his death, In the prime of life Blencowe was attacked by a violent fever, from which he was recovering, when, on 26 Aug. 1712, he shot himself during temporary insanity caused by a relapse. He was buried in All Saints Church, Northampton, where the monument to his memory records that he was a 'man studious of many kinds of learning, particularly of the common law, which he professed and practised with reputation; and of the art of deciphering letters wherein he excelled. and served the public for ten years.'